Synovial chondromatosisShaila A Nimbkar1, Sudha Y Sane1, Bhavana Patel1, RH Pathak2, AV Bavdekar2
1 Department of Pathology, Seth G. S. Medical College and K.E.M. Hospital, Parel. Bombay-100 012, India
2 Department of orthopaedic Surgery, Seth G. S. Medical College and K.E.M. Hospital, Parel. Bombay-100 012, India
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 529176
Source of Support: None, Conflict of Interest: None
Two cases of synovial ehondromatosis are presented of which one falls in a rare group o f extra-articular ehondromatosis developing in a bursa. Awareness of this rare lesion is important to prevent radical treatment owing to overdiagnosis. The histologic changes may mimic chondrosarcoma causing diagnostic problem.
Synovial chondromatosis is a rare condition in which cartilage is formed in the synovial membranes of joints, tendon sheaths or bursae by metaplasia of the connective tissue under the surface of the synovial membrane. Secondary calcification or ossification may be seen in the cartilaginous nodules but it is not always present, hence the term synovial ehondromatosis is preferred to osteo-chondromatosis.
M.H., a twenty year old male was seen in May 108 at which time he complained of a lump in the right gluteal region of 4 months' duration. He gave history of dull aching pain which increased after walking for a long time. Physical examination showed an irregular, bony hard, swelling in the right gluteal region (see [Figure 1], on page 190A). There was no warm of tenderness and the right hip joint was normal.
There was no limitation of movements of the hip joint.
Roentgenograms showed multiple areas of speckled radio-opacity in the right gluteal region appearing in connection to neck of the femur and greater trochanter (see [Figure 2], on page 190A). The hip joint was normal. Clinically, the case was diagnosed as chondrosarcoma arising from the neck of the femur.
On 26th May, wide excision of the tumor was done by postero-lateral incision of the right gluteal region. Multiple cartilaginous nodules and loose bodies were found in the bursa which was about 12 cms in diameter and was beneath the gluteus maximum muscle, reaching upto the greater trochanter. The right hip was free from the tumor. The bursa with its thickened cartilaginous wall and multiple loose bodies was excised.
Post-operatively, the patient developed haemorrhage and wound infection. Secondary suturing of the wound was done. Follow-up study has revealed that the patient's condition is good and all movements of the hip joint are normal.
The bursa was about 12 cms x 10 cms, in size with a thickened wall showing multiple, polypoid, firm projections and small cartilaginous bodies, free in the cavity (see [Figure 3], on page 190A).
The bursa was lined by synovium which showed multiple islands of cartilage in the synovial connective tissue. Many of the chondrocytes showed plump, irregular, hyperchromatic nuclei, but there were no giant cells. Calcification and ossification was seen at places (see [Figure 4] and[Figure 5] on page 190B).
S.N., a 16 year old male was first seen in April 1978, complaining of pain, swelling am restriction of movements of the right knee joint. There was no history of trauma or any history of similar complaints in other joints. There was history of fever off and on. Clinical diagnosis of tuberculosis of knee was made. Synovial biopsy was done which showed changes of mild chronic non-specific inflammation. Patient was put on antibiotics but there was no improvement. Roentgenograms of the right knee done repeatedly showed normal knee joint. In May 1978, subtotal synovectomy was done by taking antero-medial incision over the right knee. The anterior synovium was thickened and showed polypoid hard masses while posteriorly it was normal. There were no loose bodies in the joint. Histology showed a picture of synovial chondromatosis with focal areas of calcification and ossification.
Post-operative course was uneventful.
While reviewing the literature on synovial chondromatosis, it is found that the condition lacks clear definition. Although many cases are reported to be synovial chondromatosis, true synovial chondromatosis is rare, when exacting diagnostic criteria including the finding of metaplastic foci of cartilage in the synovial membrane are employed. ,, Certain authors suggested that at least some cases of multiple loose bodies not associated with active intrasynovial disease are examples of this syndrome . ,
The etiology of synovial chondromatosis remains an enigma. Many theories speculate about the role of trauma  or neoplasia.  Lexer postulated an overactivity of the embryonic rests at the junction of the synovial membrane and articular cartilage as the cause of chondromatosis. 
The condition may affect any of the diarthrodial joints of the body. The knee is the site of involvement in about two thirds of patients with the hip or elbow about equally divided as the next most frequent site. A few cases are reported with extra-articular masses of cartilage. , The term "Bursal chondromatosis" is applicable to those cases in which cartilaginous bodies develop in a bursal cavity originating from the lining of its wall. 
The males are affected twice as often as females and ages have ranged from 14 to 47 years with a peak in the 5th decade. The clinical findings are not distinctive and patients complain of various combinations of pain, swelling and limited motion. Radiological findings may be strongly suggestive of the disease in most of the cases but in about 10% of patients, no evidence may be present . 
The cytological atypia is many a times worrisome.  If the clinical and gross findings of chondromatosis show the disease confined to the synovium, the microscopic atypia can be discounted for all practical purposes. The presence of orderly ossification further favours a benign course.  The malignant change occurring in synovial chondromatosis is rare.  There are a few reports with sarcomatous change in a nodule requiring radical surgery. ,
Even in the presence of roentgenographic evidence or surgical demonstration of loose bodies, synovial chondromatosis should be distinguished from the more common causes which include osteoarthritis, osteochondritis dissecans, osteochondrol fractures, chronic infections etc., since the prognosis and treatment differ in case of synovial chondromatosis. The treatment consists, in principle, of clearing the joint of its free bodies and excising the affected synovium. Any remaining synovium constitutes a possible source of new bodies, and the synovectomy should therefore be as nearly complete as possible.
The authors thank Dr. S. G. Kinare, Professor of Pathology, and Dr. C. K. Deshpande, Dean, Seth G.S.M. College and K.E.M. Hospital for their kind permission to publish this paper.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]